Expandable porous mesh bag device and methods of use for reduction, filling, fixation, and supporting of bone

ABSTRACT

The invention provides a method of correcting numerous bone abnormalities including bone tumors and cysts, avascular necrosis of the femoral head, tibial plateau fractures and compression fractures of the spine. The abnormality may be corrected by first accessing and boring into the damaged tissue or bone and reaming out the damaged and/or diseased area using any of the presently accepted procedures or the damaged area may be prepared by expanding a bag within the damaged bone to compact cancellous bone. After removal and/or compaction of the damaged tissue the bone must be stabilized.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. patent applicationSer. No. 09/909,667, filed Jul. 20, 2001, which claims priority to U.S.Provisional Application No. 60/219,853 filed Jul. 21, 2000, the entiretyof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] This invention relates to methods and devices for correcting boneabnormalities and involves the use of a surgical mesh bag which isinserted into a prepared cavity in bone. The bag is inflated using bonereplacement material to expand and fill the cavity.

[0003] U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich, describe adevice and method for stabilizing the spinal segment with an expandable,porous fabric implant for insertion into the interior of a reamed outdisc which is packed with material to facilitate bony fusion. In thepresent invention, a similar bag is used to correct bone abnormalitiesincluding, but not limited to, bone tumors and cysts, tibial plateaufractures, avascular necrosis of the femoral head and compressionfractures of the spine.

[0004] U.S. Pat. Nos. 5,108,404 and 4,969,888 to Scholten et al.,describe a system for fixing osteoporotic bone using an inflatableballoon which compacts the bone to form a cavity into which bone cementis injected after the balloon is withdrawn. The invention requires theuse of fluoroscopy to monitor the injection and to help guard againstcement leakage through fissures in bone. Unfortunately, such leakage isknown to occur in spite of these precautions. Since such leakage maycause serious injury, including paralysis, an improved device and methodis needed.

[0005] U.S. Pat. No. 5,972,015 to Scribner et al., describes a system ofdeploying a catheter tube into the interior of a vertebra and expandinga specially configured nonporous balloon therewithin to compactcancellous bone to form a cavity. The Scribner patent approach utilizesa non-porous balloon which is inflated within the bone to causecompression. The cavity thus formed, may then be filled with bonecement. Unfortunately, the bag used by Scribner may be ruptured duringexpansion to compact cancellous bone due to sharp projections foundwithin the cavity to be expanded. Filling the cavity eventually formedcould allow leakage of bone cement out of the bone against vessels ornerves which may cause undesirable complications.

[0006] The present invention involves an improvement of all of theprevious techniques and avoids complications that could occur with thesystem of U.S. Pat. No. 5,972,015.

[0007] All U.S. patents, applications and all other published documentsmentioned anywhere in this application are incorporated herein byreference in their entirety.

[0008] The art described in this section is not intended to constitutean admission that any patent, publication or other information referredto herein is “prior art” with respect to this invention, unlessspecifically designated as such. In addition, this section should not beconstrued to mean that a search has been made or that no other pertinentinformation as defined in 37 C.F.R. § 1.56(a) exists.

SUMMARY OF THE INVENTION

[0009] The invention provides a method of correcting numerous boneabnormalities including bone tumors and cysts, avascular necrosis of thefemoral head, tibial plateau fractures and compression fractures of thespine. The abnormality may be corrected by first accessing and boringinto the damaged tissue or bone and reaming out the damaged and/ordiseased area using any of the presently accepted procedures, or thedamaged area may be prepared by expanding a bag within the damaged boneto compact cancellous bone. After removal and/or compaction of thedamaged tissue the bone must be stabilized.

[0010] In cases in which the bone is to be compacted, the methods anddevices of this invention employ a catheter tube attached to aninflatable porous fabric bag as described in U.S. Pat. Nos. 5,549,679and 5,571,189 to Kuslich, the disclosures of which are incorporatedherein by reference. Those bags may be inflated with less fear ofpuncture and leakage of the inflation medium than thin walled rubberballoons. They may also be used over a Scribner balloon to protect theballoon from breakage and eventually seepage.

[0011] The devices of U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich,additionally provide the surgeon with the advantage of safely skippingthe first balloon inflation steps of Scribner and Scholten, by expandingthe bag through introduction of fill material, such as a bone repairmedium thereby correcting the bony defect and deformity and stabilizingit in one step of the procedure.

[0012] As indicated above, the damaged bone may be removed by anyconventional reamer. Examples of reamers are described in U.S. Pat. No.5,015,255; U.S. patent application Ser. No. 09/782,176, to Kuslich etal., entitled “Expandable Reamer” and filed Feb. 13, 2001; and U.S.patent application Ser. No. 09/827,202 to Peterson et al., entitled“Circumferential Resecting Reamer Tool,” filed Apr. 5, 2001. Otherexamples of reamers are known and may be used. After the damaged bone ortissue has been removed, bone repair medium may then be inserted intothe cavity thus formed, via a catheter and expandable fabric bag asdescribed in U.S. Pat. Nos. 5,549,679 and 5,571,189.

[0013] Alternatively, either a smaller than desired cavity may be formedinto the bone to be enlarged by compaction or the cavity may be formedonly by compaction through introduction of fill material into the bag.In either case, the bag may be positioned over the inflation balloonwhich is then inflated within the bone site to provide the degree ofcompaction required. The bag may then be filled with fill material, suchas bone repair medium while the balloon remains in place within the bag.Alternatively, the balloon may be removed from the bag prior to filingthe bag.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A detailed description of the invention is hereafter describedwith specific reference being made to the drawings in which:

[0015]FIG. 1 is a side elevational view of a vertebra that is fracturedand in need of repair;

[0016]FIG. 2 is a side view of the vertebra of FIG. 1 being reamed outwith a reaming tool from the anterior approach;

[0017]FIG. 3 is a top view of the vertebra of FIG. 1 showing the reamerforming a pair of cavities within the vertebra from the anteriorapproach;

[0018]FIG. 4 is a side elevational view of the vertebra of FIG. 2showing placement of an expandable fabric bag of the invention;

[0019]FIG. 5 is a top elevational view of the vertebra of FIG. 3 showinga second of two expandable fabric bags of the invention beingpositioned;

[0020]FIG. 6 is a side view of a vertebra being reamed from a posteriorapproach;

[0021]FIG. 7 is a top view of the vertebra of FIG. 6 with a bag in placeand a second cavity being reamed;

[0022]FIG. 8 is a side elevational view of the vertebra of FIG. 6 withan expandable fabric bag of the invention in place;

[0023]FIG. 9 is a top view of the vertebra of FIG. 7 with one baginflated and the second bag being deployed;

[0024]FIG. 10 is a side elevational view showing the vertebra cavitybeing expanded with an expandable fabric bag about an inflation devicein cross-section;

[0025]FIG. 11 shows the bag system of FIG. 10 with the vertebra inphantom to show the bag system;

[0026]FIG. 12 is a view similar to FIG. 10 showing a different approachto the interior of the vertebra;

[0027]FIG. 13 is a view similar to FIG. 11 showing the approach of FIG.12;

[0028]FIG. 14 shows the bag of FIG. 12 in a closed, filled and expandedposition;

[0029]FIG. 15 is a top view of the bag system of FIG. 12 being inflatedthrough a catheter tube;

[0030]FIG. 16 shows a femoral head with avascular necrosis;

[0031]FIG. 17 shows the femoral head of FIG. 16 being reamed out;

[0032]FIG. 18 shows placement of a bag system of the invention withinthe cavity in the femoral head;

[0033]FIG. 19 is a side elevational view of a tibial plateau fracture;

[0034]FIG. 20 is a side view of the fracture of FIG. 19 with a cavitybeing formed with a reamer; and

[0035]FIG. 21 shows the tibial plateau fracture repaired with anexpanded inflatable fabric bag in place.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] In the following detailed description, similar reference numeralsare used to depict like elements in the various figures.

[0037]FIG. 1 shows a typical vertebra 10 having compression fractures 12that is in need of repair. As indicated above the damaged portion of thevertebra 10 may be reamed out, compacted, or otherwise repaired. Forexample, FIG. 2 shows a reamer 14 entering the vertebra 10 anteriorly tomake an opening 15 and cavity 16. Alternatively, multiple cavities 16may be formed such as is shown in FIG. 3.

[0038] As previously mentioned, the damaged portion of the vertebra 10may be compacted in addition to or instead of being reamed out. In FIG.4, a delivery tube or catheter 20 is seen in the process of deliveringan expandable fabric bag 22 into the vertebra 10 or into a cavity 16present therein. As indicated, the cavity 16 may have been createdthrough reaming, compaction by the bag 22 or other device, or by othermeans. Once the bag 22 is positioned within the vertebra 10, the bag 22may be inflated or expanded to the limits of the cavity 16 thus formedthrough insertion or injection of fill material 19 into the interior 21of the bag 22.

[0039]FIG. 5 shows a single filled expandable fabric bag 22 in placewith a second expandable bag which is being inserted and expanded withinthe cavity 16.

[0040] FIGS. 6-9 illustrate a procedure in which the opening 15 andcavity 16 are created posteriorly. Regardless of the direction throughwhich the vertebra 10 is operated on, in all forms, the cavity 16 whichis formed is then filled with acceptable bone replacement material.

[0041] Bone replacement material 19 may be one or more of the following,or any other biocompatible material judged to have the desiredphysiologic response:

[0042] A) Demineralized bone material, morselized bone graft, cortical,cancellous, or cortico-cancellous, including autograft, allograft, orxenograft;

[0043] B) Any bone graft substitute or combination of bone graftsubstitutes, or combinations of bone graft and bone graft substitutes,or bone inducing substances, including but not limited to: Tricalciumphosphates, Tricalcium sulfates, Tricalcium carbonates, hydroxyapatite,bone morphogenic protein, calcified and/or decalcified bone derivative;and

[0044] C) Bone cements, such as ceramic and polymethylmethacrylate bonecements.

[0045] The bone replacement material is inserted into the bag 22 via aneedle, catheter 20 or other type of fill tool. The bone replacementmaterial expands the bag to the limits of the cavity 16.

[0046] The inventive bag 22 may be a small fabric bag, from about one toabout four cm in diameter, being roughly spherical in shape, althoughother elliptical shapes and other geometric shapes may be used. The bagis pliable and malleable before its interior space 21 is filled with thecontents to be described. The material of the bag 22 may be configuredto take on the shape of the cavity in which the bag is placed. While inthis initial condition, the bag may be passed, uninflated, through arelatively small tube or portal, perhaps about three mm to about one cmin diameter.

[0047] The bag 22, such as may best be seen in FIG. 9, is constructed ina special and novel way. The bag 22 may be constructed of a fabric 23.Fabric 23 may be woven, knitted, braided or form-molded to a densitythat will allow ingress and egress of fluids and solutions and willallow the ingrowth and through-growth of blood vessels and fibroustissue and bony trabeculae, but the fabric porosity is tight enough toretain small particles of enclosed material, such as ground up bonegraft, or bone graft substitute such as hydroxyapatite or otherosteoconductive biocompatible materials known to promote bone formation.The fabric 23 defines a plurality of pores 25. Generally, the pores 25of the fabric 23 will have a diameter of about 0.25 mm or less to about5.0 mm. The size is selected to allow tissue ingrowth while containingthe material packed into the bag. If bone cement or other material isused which will not experience bone ingrowth, the pores 25 may be muchtighter to prevent egress of the media from within the bag 22 out intothe cavity 16. This prevents leakage that could impinge upon nerves,blood vessels or the like if allowed to exit the bone.

[0048] One or more of the pores 25 may be used as a fill opening 27,wherein the fabric 23 may be manipulated to enlarge a pore to a diameterpotentially greater than 5 mm but no more than about 1 cm. Preferably,the fill opening 27 is less than about 5 mm in diameter. Such apore/fill opening 27 is sufficiently large to allow a catheter, needle,fill tube or other device for inserting or injecting fill material topass through the fabric 23 and into the interior 21 of the bag 22without damaging the integrity of the bag 22.

[0049] When the bag 22 is fully filled with fill material, the bag willform a self-retaining shape which substantially fills the cavity 16.Once sufficiently full, the fill tool used to place fill material intothe bag interior 21 is removed from the opening 27. Where the opening 27is not a pore 25 but rather a separate and distinct opening in the bag22, the opening 27 may have a set diameter which requires sealing suchas by tying, fastening, welding, gluing or other means of closing theopening 27 after the bag has been filled. Where the opening 27 is a pore25, upon removal of the catheter or fill tool from the opening 27 thefabric 23 will contract to reduce the diameter of the opening 27 to besubstantially similar to that of the other pores 25.

[0050] The size and density of the pores determine the ease ordifficulty with which materials may pass through the mesh. For instance,very small pores (<0.5 mm) would prohibit passage of all but thesmallest particles and liquids. The pore size and density could becontrolled in the manufacturing process, such that the final productwould be matched to the needs of the surgeon. For example, ifmethylmethacrylate bone cement were to be used, the pore size would needto be very small, such as about less than 0.5 mm to about 1.0 mm,whereas, when bone graft or biocompatible ceramic granules are used,pore sizes ranging from about 1.0 mm to about 5.0 mm or more may beallowed. The fact that the fabric 23 is properly porous would allow itto restrict potentially dangerous flow of the fill material outside theconfines of the bag.

[0051] The fabric is light, biocompatible, flexible and easily handled,and has very good tensile strength, and thus is unlikely to rip or tearduring insertion and inflation. When the device is inflated, the deviceexpands to fill a previously excavated cavity 16.

[0052] The use of the term “fabric” herein is meant to include the usualdefinition of that term and to include any material that functions likea fabric, that is, the “fabric” of the invention must have a pluralityof pores 25 through which material and fluid flow is allowed under theterms as described, and the “fabric” must be flexible enough to allow itto be collapsed and inserted into an opening smaller than the inflatedbag size.

[0053] The bag 22 need not be woven and may be molded or otherwiseformed as is well known in the art. The preferred material may providethe ability to tailor bioabsorbance rates. Any suture-type material usedmedically may be used to form the bag 22. The bag may be formed ofplastic or even metal. In at least one embodiment, bag 22 is formedusing a combination of resorbable and/or nonresorbable thread. Bag 22may include a fill opening 27 which may be a bushing that could be abioabsorbable and/or nonbioabsorbable plastic, ceramic or metal. Theopening 27 may also be hydroxyapatite, or it could be plastic or metal.The opening 27 may also be characterized as a pore 25, wherein a pore 25of the fabric 23 has been expanded to allow a catheter 20 or other filldevice to pass into the interior 21 of the bag 22. The bag 22 could beformed from a solid material to which perforations are added. The bag 22may be partially or totally absorbable, metal, plastic, woven, solid,film or an extruded balloon.

[0054] In embodiments of the present invention a damaged tissue of abody, such as a vertebra 10 may be treated in accordance with thefollowing procedures such as are depicted in FIGS. 1-9:

[0055] Initially, the vertebra 10 needing repair is surgically exposedby forming at least one cavity 16. The cavity or cavities 16 may beformed by several different means such as by reaming. Reaming may beaccomplished by several means such as including the use of a reamer 14such as, for example, the Kuslich Expandable Reamer, U.S. Pat. No.5,015,255, the entire content of which is incorporated herein byreference. Next, the unexpanded mesh bag or Expandable Fabric Bag Device(EFBD) 22 is inserted into the cavity or cavities via catheter 20 orother means. At some point, the fill material 19 is prepared forinsertion or injection into the EFBD 22. Following preparation of thefill material 19, the material is injected or otherwise inserted intothe bag 22 using sufficient pressure to fill the bag 22 to its expandedstate, thus producing rigidity and tension within the cavity or cavities16 to reach the degree of correction required by virtue of thecompression fractures. Finally, the fill opening 27 is closed to preventegress of inflation material 19.

[0056] FIGS. 10-15 show a form of the invention in which a balloon 30and catheter tube 32 is employed. The balloon 30 is surrounded by anexpandable fabric bag 22 to protect the balloon 30 from being puncturedduring the inflation steps and to remain in place to prevent undesiredegress of material injected into the cavity formed in the bone. Balloon30 may be any medical-grade elastomeric balloon. The balloon 30 may beconstructed from latex, urethanes, thermoplasic elastomers or othersubstances suitable for use as an expandable member. Examples ofsuitable balloons include, but are not limited to: balloons utilizedwith the FOGARTY.RTM. occlusion catheter manufactured by BaxterHealthcare Corporation of Santa Ana, Calif.; balloons of the typedescribed in U.S. Pat. No. 5,972,015 to Scribner et al., and others. Themethods involve placement of the expandable fabric bag 22 of theinvention about the balloon 30 of the Scribner et al. device. Theexpandable bag 22 is left in place before the cavity 16 is filled withbone substitute or bone cement. The expandable fabric bag 22 preventsbreakage of the balloon 30 and greatly limits the ability of fillmaterial from leaking out of the cavity through bone fissures where itcould cause damage.

[0057] As may best be seen in FIGS. 11, 13 and 15, the bag 22 mayinclude a neck 29 which extends outwardly from the bag 22 to completelyoverlap the shape of balloon 30. The bag 22 and/or balloon 30 may eachhave a variety of shapes and sizes.

[0058] If desired, the expandable fabric bag 22 may be used as the soleinflation device, eliminating the Scribner et al. balloon 30 if thefabric porosity is tight and the inflation media is reasonably viscous.

[0059] While many of the previous embodiments have described the use ofthe bag 22 for repair of tissue such as a spinal body, in FIGS. 16-18show how the bag 22 may be used in treating avascular necrosis of thefemoral head. In FIG. 16, a femoral head 40 is shown which is in need ofrepair. FIG. 17 shows the femoral head being reamed out with a reamer14, such as previously described. The reamer 14 forms a cavity 16. InFIG. 18, a bag 22 is shown within the cavity 16 formed within thefemoral head 40. The opening 27 of the bag 22 is closed off after beingfilled and expanded with bone substitute material.

[0060] In an alternative embodiment, the Scribner et al. balloon, aspreviously described, may also be used with the bag 22 for repair of thefemoral head 40.

[0061] Turning to an embodiment of the invention shown in FIGS. 19-21, atibial plateau 48 is shown having a fracture 50. The fracture 50 isrepaired by forming a cavity 16 with a reamer 14, such as is shown inFIG. 20. As is shown in FIG. 21, once cavity 16 is properly reamed, bag22 may be inserted therein and filled with bone repair media 19.

[0062] Other tissue and bone abnormalities may also be treated with theinventive methods and bag 22 described herein. The present invention isnot limited to only treatment of spinal bodies, femoral heads, andtibial plateaus. The bag 22 and the methods of treatment describedherein, may be utilized throughout a mammalian body to treat many typesof bone and tissue abnormalities including those described herein aswell as others.

[0063] In addition to being directed to the specific combinations offeatures claimed below, the invention is also directed to embodimentshaving other combinations of the dependent features claimed below andother combinations of the features described above.

[0064] The above disclosure is intended to be illustrative and notexhaustive. This description will suggest many variations andalternatives to one of ordinary skill in this art. All thesealternatives and variations are intended to be included within the scopeof the claims where the term “comprising” means “including, but notlimited to.” Those familiar with the art may recognize other equivalentsto the specific embodiments described herein which equivalents are alsointended to be encompassed by the claims.

[0065] Further, the particular features presented in the dependentclaims can be combined with each other in other manners within the scopeof the invention such that the invention should be recognized as alsospecifically directed to other embodiments having any other possiblecombination of the features of the dependent claims. For instance, forpurposes of claim publication, any dependent claim which follows shouldbe taken as alternatively written in a multiple dependent form from allprior claims which possess all antecedents referenced in such dependentclaim if such multiple dependent format is an accepted format within thejurisdiction (e.g., each claim depending directly from claim 1 should bealternatively taken as depending from all previous claims). Injurisdictions where multiple dependent claim formats are restricted, thefollowing dependent claims should each be also taken as alternativelywritten in each singly dependent claim format which creates a dependencyfrom a prior antecedent-possessing claim other than the specific claimlisted in such dependent claim below (e.g., claim 3 may be taken asalternatively dependent from claim 2; claim 5 may be taken asalternatively dependent on claim 3, claim 6 may be taken asalternatively dependent from claim 3; claim 7 may be taken asalternatively dependent from claims 3, 5 or 6; etc.).

What is claimed:
 1. An implantable device for insertion into a cavity ina vertebral body comprising: a flexible container having a wallmembrane: said wall membrane defining an interior and an exterior ofsaid container; said wall having at least one hole connecting theinterior with the exterior; a fill tube coupled to said container at alocation proximate an edge of said container for injecting a flowable orfluid bone filler material into said container such that said bonefiller leaves said interior and enters said vertebral body.
 2. Thedevice of claim 1, wherein said container is substantially tubular inshape.
 3. The device of claim 1, wherein said wall membrane is elastic.4. The device of claim 1, wherein said wall membrane is inelastic. 5.The device of claim 1, wherein at least one of said wall membranes iswoven.
 6. The device of claim 1, wherein said wall membrane is porous.7. The device of claim 1, further comprising: a septum located adjacentsaid container and in fluid communication with said interior forpermitting the sealing entry of a filling device.
 8. The device of claim1, further comprising a delivery tube, wherein said container is evertedwithin said delivery tube.
 9. A method of treating an vertebral bodyhaving a superior endplate and an inferior endplate, comprising thesteps of: inserting a container into an vertebral body; deploying saidcontainer within said vertebral body; injecting a bone filler materialinto said container under pressure; whereby said pressure supplies adistraction force to move said superior and inferior endplates apart;ending injection after said endplates have moved apart.
 10. The methodof claim 9, wherein said filler material is selected from the groupcomprising: bone cement, human bone graft allograft; human bone graftautograft; synthetic derived bone substitute; sulfate and/or calciumphosphate, hydroxylapatite.
 11. A method of treating an vertebral bodycomprising the steps of: creating a cavity in the vertebral body throughan access aperture; inserting a container into said vertebral body; saidcontainer having a fill passage coupled to said container; deployingsaid container within said vertebral body; injecting a bone fillermaterial into said container through said fill passage.
 12. A method oftreating an vertebral body comprising the steps of: inserting acontainer into an vertebral body; said container having a fill passagecoupled to said container; said container having a porous outer membranesufficiently porous to allow filler material under pressure to leave thecontainer after filling the container; deploying said container withinsaid vertebral body injecting a filler material into said containerthrough said fill passage with bone filler material in a sufficientvolume to allow the bone filler material to exit the container andinterdigitates with cancellous bone within said vertebral body therebyreinforcing said bone and stabilizing fractures in said bone; saidcontainer membrane porosity sufficient to provide resistance to the flowof said bone filler material to generate force to move the endplates ofsaid vertebral body.
 13. An implantable device for insertion into acavity in a vertebral body comprising: a container including; an upperwall member; a lower wall member; a circumferential wall member; saidwall members together defining a single chamber.